Fix a Saniflo Leaking — The Trade Method
A saniflo leaking wastes water, damages fittings and can flag on a home insurance survey. Ninety percent of the time the cause is a worn washer, O-ring or cartridge — a £5 fix if you catch it early. Here is the trade method.
Step-by-step method
1. Isolate the water supply
Close the nearest isolation valve to the saniflo. If none, use the property stopcock. Open the saniflo to prove zero pressure before dismantling.
2. Identify the leak point
Dry the saniflo completely with kitchen roll. Run for 30 seconds — the first bead of water shows the exact fault: spout (cartridge/washer), body (O-ring), base (mounting seal), connections (compression olive).
3. Strip and inspect
Remove handles/covers and lift the working cartridge or washer. Take it to Screwfix, Toolstation or your merchant to match — most UK saniflos use standard 1/2" BSP or 15mm connections.
4. Refit with new seals
Grease O-rings with silicone plumbing grease (never vaseline — it swells rubber). PTFE-tape threaded joints 5 wraps clockwise. Hand-tight plus 1/4 turn — do not over-torque.
5. Refill and pressure-test
Open isolators slowly, purge air, run the saniflo for 60 seconds and check every joint with dry tissue. Re-check after 24 hours — pinhole leaks show up under thermal cycling.
Frequently asked questions
Can I fix a saniflo leaking without turning off the mains?+
Only if the saniflo has its own isolator. Otherwise close the property stopcock — attempting a repair under pressure risks a flood.
How much does fixing a saniflo leaking cost?+
DIY £3–£25 in parts. Plumber callout £70–£140. Emergency out-of-hours £120–£220.
Is a saniflo leaking an emergency?+
Only if you cannot isolate the water. A weeping fitting can wait 24 hours; an active spraying leak is a same-day call.